697 



of the auricle, obtained in this wa^', the impulse continues along 

 the atrio-ventricular systems, and causes an anticipated ventricle-systole. 

 We can compare the electrogram of this systole with those of the 

 normal periodical ventricle-systoles. It had appeared to me already 

 during my investigations into this subject in 1914^), that the electro- 

 grams of those anticipated ventricle-systoles showed R-oscillations, of 

 which the width, compared with those of the normal periodical 

 ventricle-systoles, had increased. At the same time I stated that 

 the T-osciilations of these anticipated ventricle-systoles had changed in 

 a negative sense. '■') 



We may expect, that after the compensatory 'pause during the 

 post-compensatory systole the velocity of impulse-transmission had 

 increased, and a decrease of the width of the R-oscillation of the 

 electrograms belonging to it piioved indeed, that this was the case. 

 The T-oscillation of these electrograms has changed in a positive 

 sense (a negative T-oscillation of the periodical ventricle-systoles 

 had decreased, a positive T-oscillation had increased). 



Modifications of the velocity with which the impulse was trans- 

 mitted through the ventricle were consequently expressed b}^ the 

 width of the R-oscillation and by the dimension and the direction 

 of the T-oscillation. Dni'ing the last year I continued these 

 investigations and systematically observed the changes that occurred 

 in the ventricle-electrogram, when I modified the velocity of 

 impulse-transmission. This continued investigation consists of 

 3 parts. 



1. In the first place I caused the velocity of impulse-transmission 

 to decrease by poisoning with digitalis or antiarine. Before the 

 poisoning first a photogram was made, and then, whilst the 

 poisoning continued, constantly with definite pauses a photogram 

 was made, till the halving of the ventricle-rhythm set in. As 

 the velocity of impulse-transmission suddenly increased again 

 after the halving of the ventricle-rhythm, directly an other photo- 

 gram was made. In this way I could compare the electrograms of 

 the frogs' hearts before the poisoning with those that were made 

 after the poisoning, and even before disturbances of rhythm set in. 



1) Zeitschr. fur Biologie, Bd. 65, Seite 428, 1915. 



2) By the change of the T-oscillaUon in a negative sense is meant, that a 

 positive T-oscillation of the electrograms of the periodical ventricle-systoles decreases 

 during an anticipated ventricle-systole or changes into a negative T-oscillation'. 

 If however the T-oscillation of the periodical ventricle-systoles is already negative, 

 then an increase of it during an anticipated ventricle-systole means also a change 

 in a negative sense. 



